The known coating devices for paper or cardboard webs have an application mechanism (roller mechanism or nozzle applicators), by means of which the coating material, e.g. coating dye, is applied to the web in excess. A dosing or metering system provided with a dosage element, arranged downstream of the application mechanism, wipes the excess off to leave the desired coating weight. The setting of the coating weight (weight per unit area of the coated web) is done through the contact pressure of the dosage element on the web, which in the coating region is supported by a backing roll.
During the coating of paper or cardboard webs variations of the cross section profile of the webs occur as a result of production conditions, which make it necessary to set the contact pressure of the dosage element over the work width with local differences, in order to achieve an even coating. When a doctor blade is used as the dosage element, the latter is supported at its back side by a support strip pressing from underneath, this strip being bendable within limits and adjustable along the support line by means of tension and compression screws, depending upon whether the coating weight is too high or too low at the respective locations (see German patent document DE-C 2825 907).
A generic support system is known from International patent document W)93/05887, wherein the doctor blade is supported by a flat strip, which is continuous in the area of its frontal edge resting against the doctor blade and has a number of longitudinal slits for sufficient flexibility to allow for different pressure settings of the doctor blade. A lever engages each tongue between two slits and the lever can be actuated via a pneumatic cushion, by means of which the segments of the support strip can be deformed individually in the direction of the doctor blade, in order to set a certain contact pressure.